Layer separation / delamination in resin prints
Layer separation (delamination) is when a resin print splits horizontally partway up: a clean crack, a step, or layers peeling apart like pages. The model is on the build plate, but the layers above a certain height didn't bond properly or got torn off during the peel.
Most likely causes (in order)
- Under-exposed normal layers: Each layer needs enough UV energy to bond to the one below it. If it's under-cured, the peel force tears it away.
- Lift too fast or too short: A fast lift raises peel stress, and a short lift distance may not fully release the layer from the film or let resin flow back underneath.
- Mechanical play: A loose build plate, loose vat, or wobble in the Z-axis can shift layers and leave a visible line or split.
- Running low on resin: If the vat runs low mid-print, layers form incompletely and the next ones have nothing to bond to.
Settings to change
| Setting | Change | Why |
|---|---|---|
| Normal exposure | Increase in small steps (+0.2–0.5 s) after a calibration test | Layers must bond to the previous one. |
| Lift speed / distance | Slow lift speed; increase lift distance | Reduces peel stress and lets resin flow back. |
| Hardware | Tighten plate and check Z rail; top up resin | Mechanical play causes lines (Lychee: Layer Lines). |
Exact values depend on your printer and resin. Start from the resin maker's recommended settings and change one thing at a time.
Quick checklist
- Print an exposure calibration test for this resin
- Raise normal exposure in small steps (+0.2–0.5 s) if under
- Slow lift speed and/or increase lift distance
- Tighten build plate and vat screws; check the Z rail for play
- Make sure the vat has enough resin for the whole print
- Keep resin and room roughly 20–30 °C
FAQ
Why did my resin print split in the middle?
Most often the normal layers are under-exposed or the peel is too aggressive (fast lift, short lift distance). Mechanical looseness and running out of resin are the next things to check.
Is delamination the same as layer lines?
They're related. A visible line at one height can come from a small shift or a weak bond; a full split is the same problem taken further. See our layer lines guide for banding across the whole print.
How much should I increase exposure?
In small steps, ideally guided by an exposure calibration print for your specific resin and printer. Big jumps cause over-exposure and lost detail.
Not sure which one you've got?
Upload 1–4 photos of the failed print and PrintCleric ranks the likely causes and tells you exactly which settings to change, with sources.
Sources
Related fixes
- Failed supports: model stuck to the FEP, only supports printed
- Nothing on the build plate (print stuck to the FEP)
- Suction cups and blowouts (volcanoes) in hollow resin prints
- Elephant's foot (flared bottom layers)
- Blooming and over-exposure: soft details and rough surfaces
- Cracking resin prints (hollow parts and post-curing)
Wear nitrile gloves and eye protection when handling uncured resin, and work in a ventilated space.